Compounds of the above general formula I, the tautomers, the diastereomers, the enantiomers, the mixtures thereof and the salts thereof, particularly the physiologically acceptable salts thereof, have been described in WO 01/27081 and WO 04/13099 as having valuable pharmacological properties, in particular an inhibiting effect on various kinases, especially receptor tyrosine kinases such as VEGFR2, PDGFRα, PDGFRβ, FGFR1, FGFR3, EGFR, HER2, IGF1R and HGFR, as well as complexes of CDK's (Cyclin Dependent Kinases) such as CDK1, CDK2, CDK3, CDK4, CDK5, CDK6, CDK7, CDK8 and CDK9 with their specific cyclins (A, B1, B2, C, D1, D2, D3, E, F, G1, G2, H, I and K) and to viral cyclin (cf. L. Mengtao in J. Virology 71(3), 1984-1991 (1997)), and on the proliferation of cultivated human cells, in particular endothelial cells, e.g. in angiogenesis, but also on the proliferation of other cells, in particular tumour cells.
However, none of these compounds have been described for their use in the treatment or prevention of the fibrotic diseases referred to in the present invention.
Remodeling is a normal response to tissue injury and inflammation that is observed in many tissues throughout the body. After resolution of the inflammation and repair of tissue damage, the tissue is generally returned to its original condition. Excessive uncontrolled tissue repair or the failure to stop remodeling when it is no longer required leads to condition known as fibrosis. Fibrosis is characterized by excessive deposition of extracellular matrix components and overgrowth of fibroblasts. Fibrosis can occur in all tissues but is especially prevalent in organs with frequent exposure to chemical and biological insults including the lung, skin, digestive tract, kidney, and liver (Eddy, 1996, J Am Soc Nephrol, 7(12):2495-503; Dacic et al., 2003, Am J Respir Cell Mol Biol, 29S: S5-9; Wynn, 2004, Nat Rev Immunol, 4(8):583-94). Fibrosis often severely compromises the normal function(s) of the organ and many fibrotic diseases are, in fact, life-threatening or severely disfiguring, such as idiopathic pulmonary fibrosis (IPF), liver cirrhosis, scleroderma, or renal fibrosis. Treatment options for these diseases are often limited to organ transplantation, a risky and expensive procedure.
A large body of literature implicates the platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and transforming growth factor beta (TGFb) growth factor families in the induction or persistence of fibrosis (Levitzki, Cytokine Growth Factor Rev, 2004, 15(4):229-35; Strutz et al., Kidney Intl, 2000, 57:1521-38; Strutz et al., 2003, Springer Semin Immunopathol, 24:459-76; Rice et al., 1999, Amer J Pathol, 155(1):213-221; Broekelmann et al., 1991, Proc Nat Acad Sci, 88:6642-6; Wynn, 2004, Nat Rev Immunol, 4(8):583-94).
PDGF, EGF and FGF family members are potent mitogens for mesenchymal cells such as smooth muscle cells, myofibroblasts and fibroblasts (Benito et al., 1993, Growth Regul 3(3):172-9; Simm et al, 1998, Basic Res Cardiol, 93(S3):40-3; Klagsburn, Prog Growth Factor Res, 1989, 1(4):207-35; Kirkland et al., 1998, J Am Soc Nephrol, 9(8):1464-73), the very cells which supplant normal tissue in fibrosis and are believed to play a role in tissue remodeling (Abboud, 1995, Annu Rev Physiol., 57:297-309; Jinnin et al., 2004, J Cell Physiol, online; Martinet et al., 1996, Arch Toxicol 18:127-39; Desmouliere, Cell Biology International, 1995, 19:471-6; Jelaska et al., Springer Semin Immunopathol, 2000, 21:385-95).
Inhibition of PDGF attenuates both liver fibrosis and lung fibrosis in experimental models, suggesting fibrosis in different organs may have a common origin (Borkham-Kamphorst et al., 2004, Biochem Biophys Res Commun; Rice et al., 1999, Amer J Pathol, 155(1):213-221). An EGF receptor kinase inhibitor was also active in this lung fibrosis model. Three-fold overexpression of an EGF family member, HB-EGF, in mouse pancreas islets was sufficient to cause development of fibrosis in both the exocrine and endocrine compartments (Means et al., 2003, Gastroenterology, 124(4):1020-36).
Similarly, FGF1/FGF2-deficient mice show dramatically decreased liver fibrosis after chronic carbon tetrachloride (CCl4) exposure (Yu et al., 2003, Am J Pathol, 163(4):1653-62). FGF expression is increased in human renal interstitial fibrosis where it strongly correlates with interstitial scarring (Strutz et al., 2000, Kidney Intl, 57:1521-38) as well as in a model of experimental lung fibrosis (Barrios et al., 1997, Am J Physiol, 273 (2 Pt 1):L451-8), again lending credence to the idea that fibrosis in various tissues has a common basis.
In addition, elevated levels of VEGF have been observed in several studies in persons with asthma (Hoshino et al., 2001, J Allergy Clin Immunol 107:1034-39; Hoshino et al. 2001, J Allergy Clin Immunol 107:295-301; Kanazawa et al. 2002, Thorax 57:885-8; Asai et al., J Allergy Clin Immunol 110:571-5, 2002; Kanazawa et al., 2004, Am J Respir Crit Care Med, 169:1125-30). Inducible expression of VEGF in a transgenic mouse model induces an asthma-like phenotype, edema, angiogenesis and smooth muscle hyperplasia (Lee et al., 2004, Nature Med 10:1095-1103).
Finally, TGFb stimulates production of extracellular matrix proteins including fibronectin and collagens and is believed to play an important role in fibrosis in many tissues (Leask et al., 2004, FASEB J 18(7):816-27; Bartram et al., 2004, Chest 125(2):754-65; Strutz et al., 2003, Springer Semin Immunopathol, 24:459-76; Wynn, 2004, Nat Rev Immunol, 4(8):583-94). Inhibitors of TGFb production and signaling pathways are active in a number of fibrosis animal models (Wang et al., 2002, Exp Lung Res, 28:405-17; Laping, 2003, Curr Opin Pharmacol, 3(2):204-8).
As summarized above, several growth factors are upregulated in fibrosis and the inhibition of a single factor seems to reduce the severity of fibrosis in the fibrosis models.